1. Field of the Invention
The present invention relates to an original reading device and method, and in particular, to an original reading device and method in which an original is read by using an area sensor.
2. Description of the Related Art
Japanese Patent Application Laid-Open (JP-A) No. 7-15593 has proposed an image reading device in which a prescan section and a main scan section are provided along the conveying direction of a film. The prescan section roughly reads an image recorded on the film while the film is being conveyed, so as to obtain the basic gist of the image. In accordance with the results of prescanning by the prescan section, the main scan section adjusts the density range, the measurement time and the film conveying speed for image reading, and while the film is conveyed at the adjusted conveying speed, the main scan section reads the image of the film at a high spatial resolution and a high density resolution.
The prescan section has a light source for prescanning, plural conveying roller pairs for conveying the film, a focusing lens, and a linear CCD for prescanning. Further, the main scan section has a light source for main scanning, a filter portion, a light collecting portion, conveying roller pairs, a focusing lens, and a linear CCD for main scanning. Moreover, the scanning/conveying speed in the prescan section is the same speed as or is faster than the maximum speed in the main scan section.
However, because the above-described image reading device is structured such that the prescan section and the fine scan section are provided separately, many parts are required, and the structure of the device is complex.
As described above, the prescan section and the fine scan section are disposed along the conveying direction of the film, and the scanning/conveying speed in the prescan section is the same speed as or is faster than the maximum speed in the main scan section. Therefore, an accumulator or the like for absorbing the slack in the film, which is caused by the difference in speeds between the prescan section and the main scan section, must be provided as needed between a conveying roller pair in the prescan section and a conveying roller pair in the main scan section so that the slack portion of the film is not obstructed.